From “The Book of Zen” by Tsai Chih Chung

Four monks made an agreement to meditate in silence for a week and not speak a single word.

One the first day, they maintained silence, but, as the darkness fell, the flame of the candle in their room began to flicker.

“Oh! The flame is going out!” cried the first monk.

“A-HA!” cried the second monk. “Our agreement was to not speak a single word!”

“You two have forfeited our agreement!” shouted the third.

“HA! HA! HA!” bellowed the fourth. “I am the only one who did not talk.”

The moral of the story: in admonishing others and pointing out their errors, we are very likely fallible ourselves.